[Mortality and morbidity of preterm infants--a synopsis of the german neonatal census 2001]

BACKGROUND

The German Neonatal Census provides epidemiological data in the field of perinatology particularly concerning the rates of preterm birth and the mortality and morbidity of preterm infants.

MATERIALS

All but two inquiries in Germany in 2001 were analyzed, covering 87% of all live births.

RESULTS

The transfer rate from obstetric departments to children's hospitals/neonatological wards was 14.6% of which 87.4% were singletons, 11.5% were twins and 1.1% were triplets or higher order births. 1.3% of all admitted patients were born before 32 weeks gestational age and the mortality rate was 9.1%. After 28 weeks gestational age the mortality rate was lower for twins than for singletons, after 32 weeks gestational age it was lower for triplets as well. In 17.4% of all patients born before 28 weeks gestational age a high grade intracranial hemorrhage (B III and IV) was found and in 6.2% a periventricular leukomalacia was seen. 15.8% of all surviving preterm infants before 28 weeks developed ROP 3 + >.

CONCLUSIONS

A synopsis of all neonatal censuses is an appropriate tool to study morbidity and mortality in preterm infants. Comparing the results with published data of large cohorts make the presented results reasonable although documentation seems to need some improvement in several fields.

Cerebral morbidity in preterm twins

BACKGROUND

Whether twins are more prone to increased neonatal morbidity than singletons remains controversial. It was the aim of this study to define the special risks of preterm twins with an emphasis on cerebral morbidity.

METHODS

A retrospective chart review was carried out of all consecutively born twins (n = 230) and the corresponding sets of singletons of a single level-III neonatal intensive care unit. The subjects had a gestational age between 24 and 37 weeks, and were born in 1990-98.

RESULTS

Twin pregnancies were more often complicated by preterm contractions (odds ratio (OR) 4.03 (95% confidence interval (CI) 2.39, 6.78)) whereas gestosis was significantly less (OR 0.14 (95% CI 0.05, 0.41)). Grades III and IV intracranial bleeding occurred significantly more often in twins compared to singletons (OR 3.75 (95% CI 1.65, 8.97)), with infants of less than 32 weeks' gestational age being predominantly affected (OR 3.31 (95% CI 1.33, 8.29)). Infants of less than 32 weeks' gestational age developed respiratory distress syndrome more often than the corresponding singletons (OR 1.93 (95% CI 1.15, 3.25)). There were no differences in all observed items between the first- and second-born twins.

CONCLUSION

Twins of less than 37 weeks' gestational age were significantly more often affected by high-grade intraventricular hemorrhage irrespective of birth order. Periventricular leukomalacia occurred twice as often as in singletons. There were no differences with respect to mortality and further morbidity except for respiratory distress syndrome in preterm twins of less than 32 weeks' gestational age.

Occlusive hydrocephalus in congenital myotonic dystrophy

A case of congenital myotonic dystrophy is reported which was complicated by the development of a hydrocephalus that needed ventricular-peritoneal shunting at the age of 4 months. Although dilatation of cerebral ventricles is a common feature in these patients, an occlusive hydrocephalus has not so far been reported.

[Perinatal data between 1992 and 1996]

A change of Federal Law in Germany in 1994 required the registration of premature infants with birthweights between 500 and 1000 g the previous limit being 1000 g. The data of the National Bureau of Statistics (Statistisches Bundesamt) indicate that as a consequence overall perinatal mortality increased slightly with a clear increase in premature infants with a birthweight of less than 2500 g. In all other birthweight-specific subgroups, a further decrease in perinatal mortality was observed. Overall perinatal mortality in 1996 was 0.68%.

Safety and immunogenicity of an acellular pertussis vaccine in premature infants

OBJECTIVES

To evaluate the safety and immunogenicity of a two-component acellular pertussis vaccine in preterm infants.

STUDY DESIGN

Fifty preterm infants (25-35 weeks of gestation; mean, 30.8 weeks) and 50 term infants as a control group received a two-component acellular pertussis vaccine irrespective of their biological age and actual weight. Adverse reactions were registered by parents on a diary card and reviewed on each visit. Antibodies against pertussis toxoid (PT) and filamentous hemagglutinin (FHA) were determined with an enzyme-linked immunosorbent assay before the first and after the third vaccination.

RESULTS

The infants of both groups showed an increase in geometric mean titers (GMT) against PT and FHA after vaccination (3 doses). There was a significant difference of antibody concentration between the preterm and the control group. The GMT for PT antibody of the preterm infants was 64. 16 U/L, and for the term infants it was 98.96 U/L. The GMT for FHA was 50.92 U/L in preterm versus 86.02 U/L in the control group. Efficacy of the immunization (more than a fourfold increase of antibody concentration in each infant) was 93.5% in the preterm group with respect to PT and 82.6% with respect to FHA. The incidence of adverse reactions was low and comparable in both study groups.

CONCLUSION

Immunization with an acellular pertussis vaccine is safe for preterm infants. The immune response is significantly lower compared with a control group of term infants, but efficacy is high.

Congenital unilobar pulmonary lymphangiectasis

A premature female infant is described in whom a cystic malformation of the left lung was observed on the second day of life. A lobectomy was carried out on day 31 of life, and histological examination revealed congenital pulmonary lymphangiectasis with isolated left upper lobe involvement.

A prospective, randomized, multicenter trial of high-frequency oscillatory ventilation compared with conventional ventilation in preterm infants with respiratory distress syndrome receiving surfactant

OBJECTIVES

To compare high-frequency oscillatory ventilation (HFOV) and intermittent positive pressure ventilation (IPPV) as a primary ventilation mode in preterm infants with respiratory distress syndrome. Primary end points were survival and maintenance of the randomized ventilation mode.

STUDY DESIGN

Prospective, multicenter, randomized clinical trial.

SETTING

Level III neonatal intensive care units at three university children's hospitals.

PATIENTS

Ninety-six premature infants (gestational age < 32 weeks) randomly assigned to HFOV or IPPV within the first 2 hours of life. All patients received a natural surfactant. No differences were found between the study groups with respect to the demographic data or the severity of respiratory distress syndrome. Infants were stratified at randomization, by birth weight, into two groups: 750 to 1000 gm (n = 32) and 1001 to 1500 gm (n = 64). The centers involved complied with a study protocol that planned a reduction in respiratory pressures when the infant's oxygen requirement had reached a fractional concentration of inspired oxygen of 0.6.

RESULTS

Five patients in the HFOV group died, and eight patients did not respond to the randomized ventilation mode; whereas four patients in the IPPV group died, and nine were switched to HFOV. No differences were found in gas exchange or ventilator support over the first 72 hours. Premature infants with a birth weight < 1000 gm had a significantly shorter course to reach fractional concentration of inspired oxygen of 0.21 while receiving IPPV than those receiving HFOV (9.3+/-4.5 days vs 27.5+/-10.2 days, p = 0.01). No differences were found between the groups in extraalveolar air (HFOV seven; IPPV, seven) and intracranial bleeding (HFOV, nine; IPPV, eight).

CONCLUSION

After surfactant treatment, HFOV, as a primary ventilation mode in premature infants with respiratory distress syndrome, is as safe and efficacious as conventional ventilation.

Infantile muscle phosphorylase-b-kinase deficiency. A case report

A Turkish girl is described who showed a severe floppy infant syndrome and respiratory failure at birth. She suffered upper respiratory tract infections and pneumonia. She was ventilated and had hypercapnoea secondary to bradypnoea. Biochemical analysis of skeletal muscle revealed a slightly increased glycogen content, and enzymatic analysis revealed a muscle phosphorylase-b-kinase deficiency. The infant succumbed after 140 days due to persistent apnoea and asystole. Isolated muscle phosphorylase-b-kinase deficiency should be considered as a possible diagnosis in floppy infants.

[Hemodynamic effects of high-frequency oscillating ventilation in preterm and term infants]

To study the effects of high frequency oscillating ventilation (HFOV) on cerebral and abdominal circulation we measured blood flow velocities in three cerebral arteries and in the A. mesenterica superior by pulsed doppler ultrasound in 13 preterm (mean gestational age 28 weeks [25-31]) and 3 term infants during conventional ventilation (intermitted positive pressure ventilation, IPPV) and HFOV. In the preterm infants systolic blood flow velocities decreased under HFOV in all cerebral arteries. Statistically significant differences were found in the A. cerebri anterior (45.8 cm/s [sd +/- 20.6] versus 34.3 [sd +/- 10.8]; p < 0.02) and in the A. basilaris (52.8 cm/s [sd +/- 26.4] versus 44.1 [sd +/- 18.7]; p < 0.05). There was also a distinct decrease of systolic blood flow velocity in the A. mesenterica (111 cm/s [ +/- 31.3] versus 61.8 cm/s [sd +/- 18.6]; p < 0.002). The enddiastolic blood flow velocity and the Resistance Index of Pourcelot did not change significantly. The systemic blood pressure did not change during conventional ventilation or HFOV. Mean airway pressure and pCO2 were lower during HFOV, but there was not strong correlation with the reduction of flow velocities in the studied arteries (r = 0.48). In the three term infants presenting with a persistent pulmonary hypertension of the newborn, there was an increase in systolic and enddiastolic flow velocities in all studied arteries under HFOV.

[High-frequency oscillating ventilation in premature infants under 1500 gram birth weight]

In 58 premature infants with a birthweight < 1500 g High-Frequency-Oscillating-Ventilation (HFOV) was initiated within the first 48 hours of life. Indications for HFOV were: no response to surfactant application (N = 41), respiratory distress syndrome without surfactant application (N = 9), pulmonary interstitial emphysema (N = 8). Mean gestational age of the enrolled patients was 27.6 weeks (24-32) and mean birthweight was 964 g (490-1450). 23 infants died, 5 from non-pulmonary causes. Of the remainder 2 had B-Strept.-septicemia, 1 lunghypoplasia, and 1 patient died on the 70th day of life from chronic lung disease. There were no statistical differences between survivors and nonsurvivors in gestational age, birthweight, umbilical pH, 1 min APGAR score or time on conventional ventilation prior to HFOV. Alveolar-arterial-O2-difference dropped in the group of surviving patients from x487 mm Hg (sd +/- 60) to 252 mm Hg (sd +/- 89) after 6 hours (p < 0.0001) and in the nonsurvivors from x517 mm Hg (sd +/- 74) to x373 mm Hg (sd +/- 106) (p = 0.002). Oxygenationindex fell from x25 (sd +/- 10) to x5 (sd +/- 1.5) in the survivors and from 25 (sd +/- 11) to x9 (sd +/- 5.5) in the nonsurvivors within 6 hours (p < 0.0001). Mean airway pressure could be lowered in survivors from x7.6 cm H2O (sd +/- 0.6) to 5.3 cm H2O (sd +/- 0.8) and in nonsurvivors from x8.6 cm H2O (sd +/- 0.6) to 5.7 cm H2O (sd +/- 0.9) (p = 0.0002). The promising results of HFOV as a rescue therapy require a controlled study for its use as a primary mode of ventilation in premature infants.

Intrauterine tachycardia and periventricular leukomalacia

We describe a preterm infant of 32 weeks' gestation with hydrops fetalis due to intrauterine supraventricular tachycardia. On the second day of life, cranial ultrasound showed a mainly right-sided periventricular leukomalacia already with porencephalic cysts. These findings were confirmed by autopsy. An association of intrauterine tachycardia with periventricular leukomalacia must be assumed.

[Persistent pulmonary hypertension in the newborn infant caused by aneurysm of the vein of Galen]

A male full-term neonate is described in whom cardiac insufficiency developed within 24 hours post partum. Ultrasound revealed an arterio-venous fistula of the vein of Galen. The patient's condition did not allow surgical correction and he died on the 22nd day of life. Persistent pulmonary hypertension was an important accompanying feature. The literature is reviewed with respect to the prognosis and the up to now seldom reported complication of persistent pulmonary hypertension of the newborn (PPHN).

One-sided high-frequency oscillating ventilation in the treatment of neonatal unilateral pulmonary emphysema

We describe a preterm infant (31 weeks' gestation) with unilateral pulmonary emphysema. Bronchoscopy showed no bronchial obstruction. After 20 days of right-sided high-frequency oscillating ventilation, the emphysema in the left lung had completely resolved and the patient could be extubated.